Bake-out unit for wave tube exhaust machine



Jan. 9, 1962 G. B. FLXEZAR ETAL 3,016,443

BAKE-OUT UNIT FOR WAVE TUBE EXHAUST MACHINE Filed Nov. 18, 1959 2 Sheets-Sheet 1 Illillltl Fun! usllvllllllfil wllt i.-- I l itlivlii---ill-Iii -1 Jan. 9, 1962 G. B. FLlEZAR ETAL 3,016,443

-OUT UNIT FOR WAVE TUBE EXHAUST MACHINE BAKE Filed Nov. 18, 1959 2 Sheets-Sheet 2 N 1% U Z TE 0 :5 m m is z d N E N v S sw MN o N v E: Q f l i i i: l i =3: R a i: 5 E 2 Q 4 HHH- R %Y Y L United States Patent 3,016,443 BAKE-OUT UNIT FOR WAVE TUBE EXHAUST MACHINE Geza B. Fliezar and Jack J. Monahan, Allentown, Pa., assignors to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed Nov. 18, 1959, Ser. No. 853,967 4 Claims. (Cl. 219-35) This invention relates to bake-out units, particularly ovens movable vertically relative to article holders.

In most instances, during the manufacture of articles requiring baking treatments, the articles are moved horizontally into stationary ovens provided with doors which open at the entrance ends to receive the articles and at the exit ends to permit the articles to move therefrom. However, in the present instance, the articles, which are traveling wave tubes, are supported vertically by holders movable horizontally into and out of successive treating stations, one of which is a bake-out station where it is not economically possible to employ the conventional ovens.

An object of the present invention is a bake-out unit which may efiiciently and accurately be moved into and out of baking position relative to articles to be treated.

In accordance with the object, the invention comprises a frame mounted adjacent a bake-out station and traversing a path through which articles carried by holders are moved successively, an oven closed at all portions with the exception of the bottom thereof which is open, guided in its vertical movement and caused to move by its drive means from a normal up position toan operated down position where the lower end is closed by the holder to seal the oven about the article.

In the present instance, an exhaust port disposed near the upper portion of the oven is normally closed by a door which is actuated into an open position to exhaust hot air from the oven at the end of the bake-out period and during raising of the oven to its normal position.

Other objects and advantages will be apparent from the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a side elevational view of the bake-out unit, portions thereof being broken away; and

FIG. 2 is a top plan veiw of the bake-out unit.

In the present instance, a given number of articles are removably mounted on a holder or carriage 11 which is movable in a fixed path on a track 12 through the aid of grooved wheels 14 and a pneumatic tired wheel 15. An upper surface 16 of the holder 11 lies in a given plane and serves to support an oven 17 and to close an open end 18 of the oven when in its operating position.

The oven 17 is closed at all sides as well as the top 19 and open at the bottom as illustrated in FIG. 1. The oven is formed of multiple walls of material 20 and 21, the material 20 being of the heat insulating nature, while the innermost material or lining 21, may be of a suitable dielectric material to support conductive heating elements 22. The heating elements 22 are included in suitable electrical circuits under the control of an electrical timing unit 23 to heat the interior of the oven 17 when in the operating or bake-out position shown in FIG. 1. A normally open switch 24', supported at a fixed position, is actuated closed by a projection 24' of the oven to render the unit 23 effective when the oven is down. At the end of the bake-out period, the circuits to the heating elements may be opened to permit cooling of the oven. Therefore, it should be understood that the timing unit 23 is of a commercially known type which may be set to condition the switch 24, when closed, to cause closing of the circuits to the heating elements 22. The moment 3,016,443 Patented Jan. 9, 1962 "ice these circuits are closed, the timing unit operates so that, after the selected time has passed, the circuits will be opened and held open until the oven is moved upwardly to free the switch 24. After the switch 24 is freed to open the timing unit 23 resets the circuits to be closed in response to the closing of the switch 24. As aresult, the articles in the oven are subjected to an external heat for a given length of time and before the oven is raised, the heating means is tie-energized to allow the oven to start to cool. To further assist in the cooling of the oven after the bake-out period, an exhaust port .25 located in the top 19 is opened by moving a normally closed door 26 into open position.

The oven 17 is guided in its vertical movement by pairs of apertured brackets 28 fixed to the back wall of the oven and movable relative to fixed position parallel guide rods 29 which are secured to a frame 30. The door 26 is operatively connected at 31 to one end of a bell crank lever 32 which is pivotally supported at 33 by a bracket 34 mounted on the top of the oven 17 and provided with a cam roller 35 at the other end thereof. The cam roller 35 is positioned to be engaged by a cam 36 mounted on a horizontal portion 37 of the frame 30 to cause rocking of the lever 32 to open the door 26 the moment the oven starts its upward movement and to hold the door open for a period of time during the upward movement of the oven.

The drive means for raising and lowering the oven includes a motor 40 mounted in the frame 30, the motor being of the reversible type to selectively drive a gear reduction unit 41 in reverse direction. An output shaft 42 of the gear reduction unit 41 drives a. shaft 43 through a connecting means 44. The shaft 43 is rotatably mounted in bearings 46 mounted on the'frame 30 and has drums 47 mounted on the ends of the shaft. Cables 48 have like ends fixed to their respective drums 47, extend over grooved rollers 49 rotatably mounted at 50, under grooved rollers 51 supported rotatably at 52 by the opposing sides of the oven 17, and have their other ends fixed at 53 to the horizontal portion 37 of the frame 30.

At the bake-out station, suitable means (as disclosed in detail in applicants co-pending application, Serial No. 853,968, filed November 18, 1959, now abandoned, includes a recessed member 55 of the carriage and an oper able plunger 56 mounted in the frame 31 to position and temporarily lock the carriage in the bake-out station, and a contact member 57 of the carriage to receive a contact element 58 reciprocably disposed in the frame to complete circuits from supply lines 5960 through lines 61-62 to a timing unit 63 and lines 6465 to the timing unit 23. The timing unit is for the down drive and reverse up drive of the motor 40 including normally closed limit switches 66 and 67 actuated respectively into open positions by a projection 68 of the oven when the oven reaches its down and up positions to de-energize the motor. The timing units 23 and 63 are preset for predetermined periods of time respectively to de-energize the heating elements 22 and energize the motor 40 for reverse up drive of the oven.

Operation When the carriage or holder 11 is in the bake-out station supporting its articles 10 to be treated, the oven 17, which normally is in an up position free of the articles 10, is lowered through the energization of the motor 40 in one direction. Enengization of the dlive means causes rotation of the shaft 43 to rotate the drums 47 at like speeds to pay out the cables 48 to increase the sizes of the loops of the cables supporting the oven and allow the oven to be lowered in the path guided by the rods 29 and the apertured brackets 28. At the end of the downward movement of the oven, the open bottom 1t of the oven is closed as it comes to rest on the surface 16 of the carriage or holder 11. The heating circuits are operated automatically through the unit 23, when rendered eifective by the contact member 57 and the contact ele ment 58, heating the interior of the oven to a predetermined temperature and holding this heated condition for a given length of time.

In the present instance, it is important that the interior of the oven and particularly the articles disposed therein be heated at a given temperature for a predetermined length of time but, at the end of this period, it is important that the article's be allowed'to cool. To facilitate in this action, the oven is raised through "the reversing drive of the motor 40 to wind lengths of the cables 48 upon their drums 47 and immediately upon the start of the upward movement of the oven, the door 26 is opened through the action of the cam 36 on the lever'32 to exhaust heated air from the oven through the exhaust port 25. The oven is raised'to its normal position after which the carrier or holder "11 may 'be moved 'to'the next station and another carrier or holder with articles to be bakedout moved into alignment with the oven.

It is .to be understood that the above described arerangements are simplyillustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is: t

1. A bake-out unit for articles supported 'by horizontal tops of holders movable in a given path successively into and out of a bake-out station and having contact members comprising a stationary frame mounted adjacent the station and traversing 'the'path free of the articles, an oven closed at all portions with the exception of the bottom thereof which is open, means carried by the frame to guide the oven for movement between a ,normalrposition above the path, free of the articles and holders, and an operating position with its open bottom resting on and closed by the horizontal top of one of the holders in the station, electrically energizable heating elements mounted in the oven, a first electrically operable unit adapted to control energization of the heating elements, a second electrically operable unit adapted to cause movement of the oven between said positions, a contact element supported by the frame and movable into engagement with the contact member of each holder at the station, and electrical circuits for the electrically operable units rendered effective by the engagement'of the contact element with the contact member of the holder. 7

2. A bake-out unit according to claim 1 in which an exhaust port is disposed in an upperportion of the oven, a door movably mounted on the oven and adapted normally to close the exhaust port, and meansopera'tively connected to the doorto open'the door during movement of the oven toward the normal position to exhaust heat from the oven to hasten cooling of the oven. 7

3. A bake-out unit according to claim 1 in which a timing unit supported by the'frame is included in the circuits for the second electrically operable unit and is adapted to control intervals of operation of said un-it.

- 4. A bake-out unit according to claim 1 in which a normally open switch is mounted on thc'rframe and in.- cluded in an electrical circuit for the first electrically operable unit, and a projection mounted on the oven and positioned to operate the switch into closed position as the oven is moved to rest on the holder at the station to render said first unit operable. i

References Cited in the file of this ,patent UNITED STATES PATENTS 1,467,670 Josephs et a1. Sept. 11, 1923 1,646,213 Otis Oct. 18, 1927 1,870,551 Brown Aug. '9, 1932 2,197,550 Hinsey Apr. 16, 1940 2,264,496 Wollentinet al. Dec. '2, 1941 2,275,926 Smith Mar. 10, 1942 2,721,734 Grunewald et al Oct. 25,, 1955 2,917,871 Atkeson Dec. 22, 1959 

